This renewal application request support for a three-year-period to permit continuation of a collaborative research relationship with the University of Chile, which has been supported since 1962 under Ns-03640 (to U. Chile, S. Middleton, P. I.; renewed on 06-01-75 as Ns-12470 NEAU, T. Pinto-Hamuy, P. I.) and NS-03641 (to the U. Wisconsin, C. N. Woolsey, P. I.). The University of Rochester joined in the collaboration with Chile on 03-31-72 under NS-08048 (B. Weiss, P. I.: Dr. Weiss will submit a renewal application later this year). Plans at Wisconsin for the three years of requested support will involve research on the following projects: (1) Physiological and anatomical studies on cortical visual areas (Woolsey, Montero, Guillery; Dr. Montero, now in Wisconsin, has partial support from NS-03641), (2) Central neural activity related to cardiac rhythmicity (S. Middleton, C. N. Woolsey, M.M. Gibson and J. E. Rose, Consultant; Dr. Middleton would come to Wisconsin later this year), (3) Electrophysiological correlates of conditioned avoidance learning in Bard sensory-motor remnant cats (T. Pinto-Hamuy and C.N. Woolsey; Dr. Pinto would come to Wisconsin in 1977). The funds requested would provide salary support for Chileans at Wisconsin. Other support comes from 2-PO1-NS-06225-11 (J. E. Hind, P.I.).